Bicycle Mechanics - Chainring sizes for triple crank

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Eric630
03-26-11, 07:50 PM
Building a crank and just wondering if the combination I want is possible to achieve without some kind of shifting problems, ect. What I want to use is a 50/36/22 chainring setup in the front using an I.R.D Alpina D derailleur and a 13-34 gear cassette in the rear, thanks in advance for any info
Jeff Wills
03-26-11, 10:31 PM
Building a crank and just wondering if the combination I want is possible to achieve without some kind of shifting problems, ect. What I want to use is a 50/36/22 chainring setup in the front using an I.R.D Alpina D derailleur and a 13-34 gear cassette in the rear, thanks in advance for any info
Possible? Certainly with TA Carmina crank with a 58/94mm bolt pattern spider: http://www.peterwhitecycles.com/carmina.asp . I don't think the TA chainrings are ramped & pinned, so you'll have to be patient with the shifting- it won't be as point-and-click as newer designs. Also, that's a pretty big jump from middle to outer. IMO, you're better off with a slightly larger middle chainring since you'll be going back & forth between those more often, leaving the granny for slow climbs.
FWIW: I have a 24/42/52 with an 11-34 cassette. I do a lot of cruising in the middle chainring, use the big chainring when I'm in shape, and the granny when the terrain gets vertical.
xyzzy834
03-26-11, 11:03 PM
I use a 48-36-22 setup on my touring bike with 13-34 in the back and shifted with an IRD Alpina-d front derailleur. I used a TA Zephyr crank in the past, but switched to a Deore MTB crank when I switched to a bottom bracket with outboard bearings for less bottom end flex. Same sized chainrings and cluster for both cranks.
It shifts well with Tiagra brifters.
If it's a touring bike, I'd question the need for a 50x13. If I spin out of a 48x13, I'm either riding a huge tailwind or I'm going downhill. Either way, I'll be coasting and enjoying the scenery.
Either way, I'll be coasting and enjoying the scenery.
While I appreciate the relaxed riding style, I personally always like to be pedaling. I get restless after too much coasting. My tandem has a 54/42/24 paired with an 11-32.
JohnDThompson
03-27-11, 12:26 PM
I have 47-42-24 rings on my commuter bike and it works fine:
http://www.os2.dhs.org/~john/commuter/07.jpg
Eric630
03-31-11, 12:50 PM
thanks for the info, Jeff my plan was to use the Carmina crank but I wasn't sure if the derailleur could handle it, I read somewhere that the inner chainring and outer chainring could only have a 22 teeth difference for shifting capabilities or something like that :-/ but now I have assurance the setup I want will work.
I_like_cereal
03-31-11, 01:46 PM
FSA Energy 53/39/30 with 12-25 on the rear. No problems here. BCD is 130 so replacements are a snap.
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